The invention relates to a device for sampling fluid comprising a plurality of sample vessels and means for the alternate feeding of fluid into the individual sample vessels.
In many fields of technology, in particular also that concerned with the prevention of water pollution, it is customary to take samples from fluids which are subjected to changes, for example from sewers and sewer conduits, preferably automatically at regular intervals of time. With the aid of these samples it is possible to obtain a precise picture of the state, or any changes in the state, of the fluid being analysed as well as of the chronological course of these changes. In many cases, however, in particular also in water pollution control, it is often not necessary to analyse all the samples of fluid constantly. Rather it is sufficient from time to time, or if special circumstances make it appear expedient, to make random tests. If a change in the state of the fluid is observed when making such a random test, and this change gives rise to further investigations, then the samples which have been taken during a specific period of time before this random test, for example over the previous 24 hours, are also analysed. In practice, this means that, at any time, the samples taken over a specific period of time before this time must always be available for analysis. Earlier samples, however, need not be kept.
A number of automatic devices for taking samples of fluid are already known. One of the most useful of these devices consists of a set of 24 sample vessels and a filling apparatus which charges the individual glass vessels at regular intervals of one hour per cycle. However, one of the most intrinsic disadvantages of this known device is that its sample vessels have to be emptied and rinsed each time within the duration of the cycle if it is to be avoided that, when the vessels are recharged, the new samples do not become mixed with the old ones or the residues thereof still present in them, so that the result of the analysis is falsified. This emptying and rinsing of the sample vessels requires either a constant supervision and maintenance of the the device or else, if the procedure is automatic, the provision of relatively complicated mechanical means.